Flash Joule Heating Reactor
Wesley Tingey @ unsplash.com
By instantly heating e-waste with an ultrafast jolt of electricity, this reactor can recover precious metals such as gold, silver, rhodium, and palladium for reuse, facilitating urban mining and recycling practices in a circular economy. The process is called evaporative separation, and it is solvent-free, more energy-efficient, and faster than current urban mining practices such as smelting and leaching.
First, it is necessary to crush and grind the circuit boards and add them to the reactor. The flash chamber then electrically heats this e-waste powder to 3,400 Kelvin (3,126 degrees Celsius). In less than a second, the metals are vaporized and then transported, under vacuum, into a cold trap, another vessel where the gasses condense into their constituent metals. They can then later be further refined to individual metals using other well-established purification processes.
This approach removes highly toxic heavy metals like arsenic, cadmium, chromium, lead, and mercury, leaving the remaining char with minimal metal contents, deemed safe enough for agricultural soils. This reactor was originally created to produce graphene in bulk from sources like food waste and plastic.